a region within which electrons orbit that corresponds to a fixed energy level at a given distance from the atomic nucleus of an atom.
a substance that cannot be broken down, or converted, to a simpler substance by ordinary chemical means.
a charged atom or molecule; an atom or molecule that has either an excess of electrons (and hence is negatively charged) or has lost electrons (and is positively charged).
a chemical bond formed by the electrical attraction between positively and negatively charged ions.
a subatomic particle that is found in the nuclei of atoms, bears no charge, and has a mass approximately equal to that of a proton.
non-polar covalent bond
a covalent bond with equal sharing of electrons.
a scale, with values from 0 to 14, used for measuring the relative acidity of a solution; at pH 7 a solution is neutral, pH 0 to 7 is acidic, and pH 7 to 14 is basic; each unit on the scale represents a tenfold change in concentration.
polar covalent bond
a covalent bond with unequal sharing of electrons, such that one atom is relatively negative and the other is relatively positive.
a subatomic particle that is found in the nuclei of atoms, bears a unit of positive charge, and has a relatively large mass, roughly equal to the mass of the neutron.
a liquid capable of dissolving (uniformly dispersing) other substances in itself.
the property of a liquid to resist penetration by objects at its interface with the air, due to cohesion between molecules of the liquid.
the weak attraction between a hydrogen atom that bears a partial positive charge (due to polar covalent bonding with another atom) and another atom, normally oxygen or nitrogen, that bears a partial negative charge; hydrogen bonds may form between atoms of a single molecule or of different molecules.
a particle composed of one or more atoms held together by chemical bonds; the smallest particle of a compound that displays all the properties of that compound.